cardme is a Java library implementation of RFC 2426, VCard. It provides Java applications with a way to read and write from and to the VCard file format. The project's goals are to provide a flexible and easy to use library with excellent documentation.

Address Book Server allows you to share your
contacts and calendar events with others connected
to your network or over the Internet. Each
participant synchronizes their contacts with the
server hosted on your own system. Address Book
Server supports the full Address Book and iCal
schema. The server also provides a friendly Web
interface and an iPhone client which let you
access your contact details remotely.